Theoretical Implications of Thermal Emission from Gamma-Ray Bursts
2009 (English)In: GAMMA-RAY BURST / [ed] Meegan, C; Gehrels, N; Kouveliotou, C, 2009, Vol. 1133, 317-322 p.Conference paper (Other academic)
Recent analysis show evidence for a thermal emission component that accompanies the non-thermal emission during the prompt phase of GRBs. We show that this component is naturally explained by considering emission from the photosphere. The photosphere of a relativistically expanding plasma wind strongly depends on the angle to the line of sight, θs. As a result, thermal emission can be seen after tens of seconds. Using probability density function P(r,θs) to describe photon escape at radius r and angle θs, we show that the thermal flux is expected to decay at late times as F$_BB$~t$^-2$, and the observed temperature decays as T~t$^-Î±$, with α~1/2-2/3. We discuss the relation between thermal emission and high energy, non-thermal spectra observed by FERMI. We show how thermal emission can be used to directly measure the Lorentz factor of the flow and the initial radius of the jet.
Place, publisher, year, edition, pages
2009. Vol. 1133, 317-322 p.
, AIP Conference Proceedings, ISSN 0094-243X ; 1133
gamma-ray sources; gamma-ray bursts, Radiation belts, Density functional theory, local density approximation, gradient and other corrections
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:kth:diva-81246DOI: 10.1063/1.3155909ISI: 000267717300076ScopusID: 2-s2.0-70450193476OAI: oai:DiVA.org:kth-81246DiVA: diva2:497425
6th Huntsville Symposium on Gamma-Ray Burst. Huntsville, AL. OCT 20-23, 2008
QC 201203022012-02-102012-02-102012-03-02Bibliographically approved